1. Field of the Invention
The present invention relates to a recording medium and an ink-jet recording process using such a recording medium.
2. Related Background Art
An ink-jet recording system is a system wherein minute droplets of an ink are ejected from orifices to apply them to a recording medium such as paper, thereby making a record of images, characters and/or the like, has such features that recording can be conducted at high speed and with low noise, color images can be formed with ease, and development is unnecessary, and is hence developed into information instruments such as printers copying machines, word processors, facsimiles and plotters, so that it is rapidly widespread.
In recent years, high-performance digital cameras, digital video cameras and scanners have begun to be provided cheaply, and occasion to output image information obtained from such instruments by an ink-jet recording system has increased conjointly with the spread of personal computers. Therefore, there is a demand for outputting images comparable in quality with silver salt photographs and multi-color prints made by a plate-making system using an ink-jet system.
Improvements in recording apparatus and recording systems, such as speeding up and high definition of recording, and full-coloring of images, have thus been made, and recording media have also been required to have improved properties.
Under the foregoing circumstances, recording media are generally required to have the following properties:
(1) being able to quickly absorb inks and prevent more feathering than recording needs; PA1 (2) being able to provide a print having a high optical density and achieve high coloring ability; PA1 (3) being able to provide a print having excellent weather fastness; and PA1 (4) being able to provide a glossy image.
In order to satisfy such requirements, a wide variety of proposals has been made. For example, it is described in Japanese Patent Application Laid-Open No. 59-22683 that in order to provide a printing sheet having good ink absorbency and gloss, at least two thermoplastic resins different from each other in the lowest film-forming temperature are applied to a surface of a base material and dried to form a film, thereby causing cracks in the surface.
It is also described in Japanese Patent Application Laid-Open Nos. 59-222381, 6-55870, 7-237348 and 8-2090 that in order to improve the water fastness and weather fastness of images formed, a layer containing thermoplastic resin particles is provided as a surface layer to form the surface layer into a film after printing.
However, the particle size distribution of thermoplastic resin particles is generally broad and includes various particle sizes. When a porous layer is formed with the thermoplastic resin particles having such a broad particle size distribution, particles of small sizes fill in voids formed among particles of large sizes. Further, the small particles are softened at a temperature lower than the glass transition temperature (Tg) of the resin so long as the temperature is close to Tg because heat is more effectively applied to particles of smaller sizes, so that the voids are more closely filled with the small particles. Therefore, the ink-absorbing speed of the resultant recording medium is slowed. As a result, such a recording medium has undergone bleeding at boundaries between different colors, and caused color irregularity (beading).
In addition, the feathering rate of inks has become low, so that in some cases, blank areas may have been caused due to formation of printed dots relatively small in diameter and distortion of dots, and the quality of images formed may have become poor.